Plate clamp



July 27, 1948- T. c. P. TUNNARD-MooRE 2,446,030

PLATEV CLAMP Filed May 8, 1946 Tkwwas Cantu fog/wb /fmuwl Patented July 27, 1948 OFFICE PLATE CLAMP Thomas Charles Poynder Tunnard-Moore,

Hendon Way, London, England Application May 8, 1946, Serial No. 668,189 In Great Britain November 3, 1945 1 Claim. 1

This invention relates to plate clamping devices and has for its object to combine the advantages of two known types in each of which a pin, adapted for engagement with registering holes in plates to be subsequently riveted or otherwise secured together, is formed with a recess at one side so as to produce a shoulder near its free end, and is mounted to slide in a relatively stationary part provided with a projection or shrouding which fits against the side of the pin remote from said recess, the cross-sectional dimensions of the projection or shrouding 'and of the recessed part of the pin being together substantially equal to the cross-sectional dimensions of the full diameter of the pin.

In one known type of clamping device of this kind the required clamping pressure is resilient and obtained solely by means of a spring which, in order to provide the required clamping pressure, is so powerful as to involve the use of a tool to compress it when inserting the pin in the holes in the plates.

In the other known type the clamping pressure is mechanical fand obtained solely by means of a nut screwing onto the rear end of the pin and taking a bearing -against a holder therefor` The clamping device of the present invention is distinguished from the iirst of the two known types above referred to in that it dispenses with the need for a tool by using a weaker spring and provides means for `augmenting the clamping pressure exerted thereby. The improved clamping device is also distinguished from the second of the two known types herein referred to in that it includes means for providing an initial clamping pressure of a, resilient nature sufficient to |hold the device in engagement with the plates during the application of further pressure by mechanical means, thereby facilitating the use of the device and obtaining the advantages of a controlled pressure.

In the accompanying drawing,

Figure l is a view in side elevation of the improved clamping device.

Figure 2 is a front view thereof.

Figure 3 is a, view of the device in axial plane section, including a portion of two plates to be clamped together.

Figure 4 is a detail view of the projection or shrouding.

Figure 5 is a view similar to Figure 3 showing the device in its operative position.

Figure 6 isa detail view of the adjustable collar.

Referring to the drawing, 2 represents the pin, which is slidably mounted in the holder 3 and screw-threaded at its rear end to` take a nut 4 adapted to bear against the back of the holder. Normally, the said pin according to the present invention is held in a retracted position in the holder by means of a spring 5 arranged within the holder between the shouldered inner end 6 of an axial hole therein and a collar 1 adjustably mounted on the rear end of the pin. The strength of this spring is such that relative axial movement between the holder and the pin can be effected bycne hand, the arrangement being such that, in introducing the front end of the pin into the registering holes in the plates 8, 9 to be clamped tog-ether, the operator holds the device between two ngers with the rear end of the pin bearing against his thumb. The pin can then be pushed forward by the thumb relatively to the holder and against the pressure of the spring a distance suliicient to allow the protruding front end of the pin and the shrouding or projection I0 carried by the holder to be inserted in the holes in the said plates. On now releasing the device the spring retracts the pin until the shoulder Za thereof formed by the cutaway portion Zb abuts against the inner face of the innermost plate 9, pulling the plates together until the outer face of the front plate 8 abuts against the front end of the holder. The holes in the sheets are now accurately aligned, being completely lled, as seen in Figure 5, by the sum of tlhe cut-away portion of the pin and the projection or shronding which together have a diameter equal to that of the hole.

If -the clamping pressure of the spring is found to be insufficient to hold the plates firmly together, the pressure may be augmented by screwing up the nut 4 on the rear end of the pin against the back of the holder 3.

In the device shown the projection or shrouding l0 instead of being made integral with the holder, as formerly, is made as a separate part, see Figure 4, with a head lllEL which abuts against the inside of the shouldered end 6 of the Ihole in the holder and is formed with a hole equal to the full diameter of the pin.

The improved device is further distinguished from devices of the general type herein referred to in that the holder, instead of having a central `hole at the ront partly closed by `a plate having an eccentric hole, is formed with the shoulder 6 having an eccentric hole to accommodate the `shrouding I0 and the reduced part 2b of the pin.

I claim: A plate clamp comprising in combination a holder, a screw threaded pin having a gapped portion thereon slidably mounted in said holder, REFERENCES CITED a shrouding having a part which is adapted to project beyond said holder at one end with a l'ho gwgrerens are of record m the collar formed on the other end which is disposed Witlhin said holder, and in which said pin slides, 5 UNITED STATES PATENTS a collar threaded on said screwed pin, a com- Number Name Date pression spring disposed between the collar and 25161;464 `Gilbert Junef6y1939 the collar on the shrouding to normally retain this 2,175,313 Rosenberry "Oct 10,1939

ber mounted on the screwed p-in for augmenting l0 the clamping pressure on said pin. THOMAS CHARLES POYNDER TUNNARD-MOORE.

pin in its retracted position and a screwed mem- 2,36%353 Edwards Jan. 23, 1945 

